I may be missing something from the question. The good-old CTRL+C and CTRL+V works between Excel & PowerPoint.
If you want to place only the chart from Excel then … highlight the graph & copy by holding down Ctrl +C. Now on the PowerPoint slide click on the area that you want the graph to be placed & then paste (Ctrl+V). You can now re-size & move the graph by clicking on the graph & then moving the “handles”. The underlying data for the chart is automatically copied. If you want to change the data in PowerPoint then right click on the chart & select “Edit Data”. Excel like page will open up – you can change the data & dynamically can see the effect on the chart.
It seems complicated … but it is fairly easy. My description may be too verbose. This is true in Excel 2007 & PowerPoint 2007. I am sure it is very similar is 2003 version. You are welcome to post again if further questions. Good luck.